Lower-Extremity Neuromuscular Function Following Concussion: A Preliminary Examination

Landon B. Lempke, Jarrod A. Call, Matthew C. Hoch, Julianne D. Schmidt, Robert C. Lynall

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


postconcussion musculoskeletal injury risk. Existing research has only examined voluntary muscle activation, limiting mechanistic understanding. Therefore, our study aimed to examine voluntary and involuntary muscle activation between college-aged, concussed individuals when symptom-free and healthy matched controls. Design: Prospective, cross-sectional cohort laboratory study. Methods: Concussed and healthy participants (n = 24; 58% male, age: 19.3 [1.1] y, mass: 70.3 [16.4] kg, height: 177.3 [12.7] cm) completed the superimposed burst (SB) neuromuscular assessment on their dominant limb within 72 hours after self-reporting asymptomatic (22.4 [20.2] d postinjury). Unnormalized and bodyweight-normalized quadriceps maximal voluntary isometric contraction torque (in newton meters), unnormalized and bodyweight-normalized electrically stimulated SB torque, pain (numeric 1-10) during SB, and the central activation ratio (in percentage) were assessed via the SB. Parametric and nonparametric analyses, 95% confidence intervals (95% CIs), and Hedges g (parametric) and Spearman ρ (nonparametric) effect sizes were used to examine group differences (α = .05). Results: The maximal voluntary isometric contraction torque (concussed: 635.60 N m [300.93] vs control: 556.27 N m [182.46]; 95% CI, -131.36 to 290.02; P = .443; d = 0.33), SB torque (concussed: 203.22 N m [97.17], control: 262.85 N m [159.07]; 95% CI, -171.22 to 51.97; P = .280; d = -0.47), and central activation ratio (concussed: 72.16% [17.16], control: 70.09% [12.63]; 95% CI, -10.68 to 14.83; P = .740; d = 0.14) did not differ between the concussed and control groups regardless of bodyweight normalization (P ≥ .344). Pain during the SB was significantly higher with a medium effect for participants with a concussion versus healthy controls (concussed: median = 7, control: median = 5; P = .046; ρ = -0.42). Discussion: These findings suggest concussed participants do not have statistically altered voluntary or involuntary quadricep neuromuscular function once asymptomatic compared with controls. Therefore, the elevated postconcussion musculoskeletal injury risk may not be attributed to lowerextremity muscle activation. Concussed participants displayed greater pain perception during the SB, which suggests somatosensory or perception changes requiring further examination.

Original languageEnglish
Pages (from-to)31-39
Number of pages9
JournalJournal of Sport Rehabilitation
Issue number1
StatePublished - Jan 2023

Bibliographical note

Publisher Copyright:
© 2023 Human Kinetics, Inc.


  • interpolated twitch
  • kinesiophobia
  • mild traumatic brain injury
  • sensorimotor

ASJC Scopus subject areas

  • Biophysics
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation
  • Rehabilitation


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